package com.dcy.znoa.common.util.password;

/* Copyright 2004, 2005, 2006 Acegi Technology Pty Limited
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*     http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

import org.springframework.dao.DataAccessException;


/**
* <p>
* Interface for performing authentication operations on a password.
* </p>
*
* @author colin sampaleanu
* @version $Id: PasswordEncoder.java 2217 2007-10-27 00:45:30Z luke_t $
*/
public interface PasswordEncoder {
   //~ Methods ========================================================================================================

   /**
    * <p>Encodes the specified raw password with an implementation specific algorithm.</p>
    *  <P>This will generally be a one-way message digest such as MD5 or SHA, but may also be a plaintext
    * variant which does no encoding at all, but rather returns the same password it was fed. The latter is useful to
    * plug in when the original password must be stored as-is.</p>
    *  <p>The specified salt will potentially be used by the implementation to "salt" the initial value before
    * encoding. A salt is usually a user-specific value which is added to the password before the digest is computed.
    * This means that computation of digests for common dictionary words will be different than those in the backend
    * store, because the dictionary word digests will not reflect the addition of the salt. If a per-user salt is
    * used (rather than a system-wide salt), it also means users with the same password will have different digest
    * encoded passwords in the backend store.</p>
    *  <P>If a salt value is provided, the same salt value must be use when calling the  {@link
    * #isPasswordValid(String, String, Object)} method. Note that a specific implementation may choose to ignore the
    * salt value (via <code>null</code>), or provide its own.</p>
    *
    * @param rawPass the password to encode
    * @param salt optionally used by the implementation to "salt" the raw password before encoding. A
    *        <code>null</code> value is legal.
    *
    * @return encoded password
    *
    * @throws DataAccessException DOCUMENT ME!
    */
   String encodePassword(String rawPass, Object salt)
       throws DataAccessException;

   /**
    * <p>Validates a specified "raw" password against an encoded password.</p>
    *  <P>The encoded password should have previously been generated by {@link #encodePassword(String,
    * Object)}. This method will encode the <code>rawPass</code> (using the optional <code>salt</code>),  and then
    * compared it with the presented <code>encPass</code>.</p>
    *  <p>For a discussion of salts, please refer to {@link #encodePassword(String, Object)}.</p>
    *
    * @param encPass a pre-encoded password
    * @param rawPass a raw password to encode and compare against the pre-encoded password
    * @param salt optionally used by the implementation to "salt" the raw password before encoding. A
    *        <code>null</code> value is legal.
    *
    * @return true if the password is valid , false otherwise
    *
    * @throws DataAccessException DOCUMENT ME!
    */
   boolean isPasswordValid(String encPass, String rawPass, Object salt)
       throws DataAccessException;
}
